Abstract
Sea-Lab Formula 28 is a mixture of naturally occurring buffer compounds that maintains natural ocean concentrations of calcium, strontium, and all 15 essential trace elements
Here are my random opinions on it....
But doesn't water changes do this anyways? Don't most Calcium/Alkalinity supplementation methods also do this? It sounds nice, but it looks like to me that this would be an easy way to screw up tank chemistry if not properly done. Heck, it just might be a concentrated block of pickling lime.
Also, every tank is different on how quickly and at what levels it uses Carbonate and Calcium. This would just replace it back in equal levels, but someone's tank might use Calcium quicker than Carbonate. So, at $18.99 for one block and you still have to supplement what gets used up too quickly, what's the point? You can accomplish the same goal with Limewater. And you can get a huge container for $2.59 at WalMart where it is often readily available and not ordered online.
Plus, why does this dissolve? What is the bonding agent? It couldn't be condensed aragonite. It would need a lower pH in order for it to start to dissolve.